JP4032006B2 - Film carrier tape for mounting electronic components - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a film carrier tape (TAB (Tape Automated Bonding) tape) for mounting electronic components with few defects such as pinholes. More specifically, the present invention relates to a film resist tape for mounting electronic components with few defects such as pinholes and a solder resist that leaves a lead portion for joining a wiring pattern formed in a desired shape on an insulating film to a pump of a device. The present invention relates to an electronic component mounting film carrier tape (TAB tape) that hardly causes pinholes in an applied solder resist when a film carrier tape (TAB tape) for mounting an electronic component including a step of coating is manufactured.
[0002]
TECHNICAL BACKGROUND OF THE INVENTION
A film carrier tape (TAB tape) for mounting electronic components is obtained by attaching a copper foil to an insulating film such as a polyimide film, applying a photoresist on the copper foil, and exposing the photoresist to a desired shape. After removing unnecessary parts and masking, etching with acid to etch the copper foil into the desired pattern, removing the masking agent, and applying the solder resist except the formed lead part, then lead part For example, it is manufactured by forming a eutectic with a bump of a device such as tin, and performing metal plating capable of bonding the device.
[0003]
In the manufacture of such TAB tape, the solder resist is used as a coating solution dissolved or dispersed in an organic solvent so that an insulating resin can be applied, and screen printing is performed on the surface on which the wiring pattern is formed. It is applied using technology.
[0004]
By applying the solder resist in this way, the formed wiring pattern is protected, adjacent wiring patterns are reliably insulated from each other, and further, it becomes a masking agent in the next plating process.
[0005]
This solder resist layer is formed by applying a solution in which an epoxy resin or a polyimide resin is dissolved or dispersed in a solvent, usually to a thickness of about 10 μm, and heating to a temperature of about 120 to 160 ° C. It is formed by curing the resin.
[0006]
However, such solder resist coating liquid contains fine bubbles, and these fine bubbles form voids or pinholes in the solder resist layer when the solder resist coating liquid is heated and cured after coating. To do. In conventional TAB tapes with a wide lead pitch, these voids or pinholes rarely become a problem, but in TAB tapes with fine pitches where the pitch width currently attracting attention is less than 100 μm, Even if slight voids or pinholes are generated, there is a problem that the reliability of the electronic device is lowered due to, for example, migration that may occur between wiring patterns.
[0007]
In order to prevent the occurrence of such voids or pinholes, for example, Japanese Patent Application Laid-Open No. 8-124968 discloses that “in a method of manufacturing a TAB tape for TCP having a coating layer for protection and insulation between wirings in a vacuum. “A method for producing a TAB tape for TCP, wherein the coating layer is formed by drying and reaction solidification by baking treatment”.
[0008]
However, the method disclosed in this publication is intended to remove bubbles contained in the solder resist layer before the solder resist is hardened by performing a baking process in a vacuum, and therefore, a solder resist coating solution. Inside, fine bubbles are contained as in the conventional case. By curing the solder resist under reduced pressure conditions, the bubbles contained in the solder resist layer can be easily removed. However, as long as the solder resist coating liquid itself contains bubbles, the contained bubbles are completely removed. It is almost impossible to do so, and even this method cannot completely prevent the generation of voids or pinholes.
[0009]
By the way, when preparing a solder resist coating solution, a small amount of a silicone-based antifoaming agent is blended in the solder resist coating solution so that fine bubbles (bubbles) are not contained by the air entrained in the solder resist coating solution. It is common to do. Such a silicone-based antifoaming agent has an excellent defoaming action, and by blending such a silicone-based antifoaming agent, the amount of bubbles contained in the solder resist coating solution can be greatly reduced. The use of silicone antifoaming agent is extremely effective as a means for preventing the formation of voids or pinholes.
[0010]
By the way, after mounting a device on a TAB tape, the TAB tape is used by sealing an area including the device with a resin. However, since silicone antifoaming agents have low compatibility with other resins and high heat resistance, they exude to the solder resist surface when the solder resist is heated and cured, and this exuding silicone antifoaming agent The sealing resin may be repelled by the agent, and the bonded device may not be completely sealed.
[0011]
In addition, the silicone-based antifoaming agent that has oozed out when the solder resist is cured may adhere to the inner lead surface and the like, and it is extremely difficult to remove the silicone-based antifoaming agent thus adhered. And when a silicone type antifoamer adheres to an inner lead in this way, there also exists a problem that a connection defect tends to arise between an inner lead and a bump of a device.
[0012]
OBJECT OF THE INVENTION
An object of this invention is to provide the TAB tape in which the soldering resist layer with very few defects, such as a pinhole, was formed. Another object of the present invention is to provide a TAB tape in which the sealing resin is not repelled when a region including the mounted device is sealed with resin after the device is mounted on the inner lead. It is said.
[0013]
A further object of the present invention is to provide a TAB tape with good connectivity between inner leads and device bumps.
[0014]
SUMMARY OF THE INVENTION
  The film carrier tape for mounting electronic components according to the present invention has a desired wiring pattern formed on the surface of the insulating film, and a urethane resin is formed on the wiring pattern except for the lead portionOrA solder resist coating layer formed by coating a defoaming solder resist coating solution containing a modified urethane resin elastomer using a screen mask coating in the range of 120 to 165 mesh is applied at a normal pressure within a range of 40 to 170 ° C. A solder resist layer having a thickness of 25 to 40 μm made of a cured product formed by raising the temperature is formed, and no pinhole or void is formed in the solder resist layer, and the film carrier tape InInner lead without silicone antifoamAnd theInner lead without silicone antifoamIs characterized in that a tin plating layer having a thickness of 0.1 to 0.6 μm, in which copper is diffused in part, is formed.
[0015]
  The film carrier tape for mounting electronic components of the present invention is a wiring pattern excluding a lead portion formed by etching after bonding a copper foil to an insulating film surface and etching the copper foil to form a desired wiring pattern. In the method for producing a film carrier tape for mounting electronic components, which has a step of coating a solder resist so as to cover the solder resist, the solder resist coating solution has an average coating thickness.25-40It can manufacture by apply | coating so that it may exist in the range of micrometer, and the apply | coated soldering resist layer does not have a pinhole substantially.
[0016]
The solder resist coating solution used in the present invention contains a curable resin dissolved or dispersed in an organic solvent, and the solder resist coating solution does not contain a component having a siloxane skeleton. That is, the solder resist coating solution used in the present invention does not substantially contain a silicone-based antifoaming agent.
[0017]
When the coating solution is foamed during the preparation of the solder resist coating solution, etc., the generated foam is included in the coating solution, and voids or pinholes are formed in the solder resist layer by the included bubbles. In order to prevent foaming, the solder resist coating solution contains an antifoaming agent. The most effective antifoaming agent is a silicone-based antifoaming agent. However, when a silicone-based antifoaming agent is added to the solder resist coating solution, the silicone-based antifoaming agent is likely to ooze out on the surface when the solder resist is heated and cured. After bonding the device, the vicinity of this device is sealed with resin. Even if it tries to do so, the problem arises that the resin is repelled by the silicone-based antifoaming agent that has exuded. The repellency of this resin is particularly prominent on the base film. Further, it was found that when the exuded (bleeded) silicone-based antifoaming agent adheres to the surface of the inner lead, a bonding failure of the device occurs.
[0018]
The above problems will not occur unless a silicone-based antifoaming agent is added, but when preparing a solder resist coating solution, fine bubbles tend to be contained in the coating solution, and fine bubbles are formed in the formed solder resist layer. By removing, voids or pinholes are formed.
[0019]
The inventor has various problems as described above, but without using a silicone-based antifoaming agent that is still used because of its high antifoaming effect, TAB is less likely to generate voids or pinholes. As a result of studying the tape method, firstly, it was found that generation of voids or pinholes can be prevented by keeping the thickness of the solder resist layer within a certain range. Furthermore, in addition to the thickness of the solder resist layer, by improving the method of stirring the solder resist coating solution, the method of applying the solder resist, and the coating device, it has conventionally been considered that the silicone system that must always be used Generation of voids or pinholes can be prevented without using an antifoaming agent.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Next, the TAB tape of the present invention and the method for producing the TAB tape will be specifically described.
[0021]
As shown in FIG. 1 and FIG. 2, an electronic component mounting film carrier tape 1 according to the present invention has an insulating film 10 and a wiring pattern made of an electrolytic copper foil adhered to the surface with, for example, an adhesive layer 12. 30 are stacked in this order. This electrolytic copper foil is coated with a photoresist on the top surface, exposed to a desired pattern, developed, and then etched by using an acid or the like to form a desired wiring pattern 30. A solder resist 20 is applied to protect the surface of the wiring pattern 30 except for the inner lead or outer lead portion.
[0022]
The insulating film 10 constituting the electronic component mounting film carrier tape of the present invention is made of a flexible resin film. Further, the insulating film 10 has chemical resistance that is not affected by such chemicals because it comes into contact with an acid during etching, and heat resistance that does not deteriorate due to heating during bonding. Examples of such a flexible resin film include glass epoxy, BT resin, polyester, polyamide, and polyimide. In particular, in the present invention, it is preferable to use a film made of polyimide.
[0023]
Examples of the polyimide film constituting the insulating film 10 include fully aromatic polyimide synthesized from pyromellitic dianhydride and aromatic diamine, and biphenyl synthesized from biphenyltetracarboxylic dianhydride and aromatic diamine. Mention may be made of wholly aromatic polyimides having a skeleton. In particular, in the present invention, a wholly aromatic polyimide having a biphenyl skeleton (eg, trade name: Upilex, manufactured by Ube Industries, Ltd.) is preferably used. The thickness of the insulating film 10 is usually in the range of 25 to 125 μm, preferably 50 to 75 μm.
[0024]
When such an insulating film 10 has a device hole 41, a sprocket hole 42, a cut hole of an outer lead, and a bent portion, a flex slit or the like is formed by punching at the bent position.
[0025]
The wiring pattern 30 forms an adhesive layer 12 by applying an insulating adhesive to at least one surface of the insulating film 10 in which the predetermined holes 41, 42... Are formed as described above. The adhesive layer 12 is formed by bonding a copper foil and etching the copper foil. Here, as the copper foil, either an electrolytic copper foil or a rolled copper foil can be used. In the present invention, it is preferable to use an electrolytic copper foil that can cope with the recent fine pitch.
[0026]
The adhesive used here needs to have characteristics such as heat resistance, chemical resistance, adhesive strength, and flexibility. Examples of adhesives having such characteristics include epoxy adhesives and phenolic adhesives. Such an adhesive may be modified with a urethane resin, a melamine resin, a polyvinyl acetal resin, or the like, or the epoxy resin itself may be rubber-modified. Such adhesives are usually heat curable. The thickness of such an adhesive layer is usually in the range of 8 to 23 μm, preferably 10 to 21 μm. In addition, when sticking copper foil to the above insulating films 10, it can also stick without using an adhesive agent.
[0027]
The adhesive layer 12 made of such an adhesive may be applied on the surface of the insulating film 10 or may be applied on the surface of the electrolytic copper foil. As the electrolytic copper foil used here, a copper foil having a thickness usually used in the manufacture of a TAB tape can be used, but in order to manufacture a fine pitch TAB tape, the copper foil is usually used as a copper foil. A copper foil in the range of 6 to 75 μm, preferably 9 to 75 μm, more preferably 9 to 50 μm is used. By using such a thin electrolytic copper foil, it becomes possible to easily form an inner lead with a narrow pitch width.
[0028]
After affixing the copper foil to the surface of the insulating film in this way, a photoresist is applied to the surface of the copper foil, and a desired wiring pattern is baked on the photoresist to cure the photoresist. Remove the photoresist. Conversely, a photoresist that can be dissolved in a specific medium by exposure can also be used.
[0029]
The copper foil on which the desired wiring pattern is formed by the photoresist thus cured is etched to dissolve and remove the copper foil where the photoresist does not exist, thereby forming the wiring pattern 30 made of copper foil on the surface of the insulating film. .
[0030]
After the wiring pattern 30 is thus formed by etching, the hardened photoresist is removed, for example, with an alkaline solution.
[0031]
In the present invention, after a predetermined wiring pattern is formed in this way, a solder resist coating solution is applied except for the tips of the inner lead 51 and outer lead 52 to be plated in the next step.
[0032]
In the solder resist coating solution used in the present invention, a curable resin is dissolved or dispersed in an organic solvent, and the solder resist coating solution preferably contains no silicone antifoaming agent.
[0033]
  The curable resin contained in the solder resist coating solution used in the present invention is, Urethane resins, elastomer modified products of urethane resinsIt is preferable to contain. It is particularly preferable to use a modified elastomer. For this elastomer modificationTo urethane resinA method of modifying by mixing elastomer components;, Urethane resinThere is a method of copolymerizing a monomer that forms an elastomer and a monomer that forms an elastomer. In the present invention, any modified elastomer can be used. It is particularly preferable to use an elastomer-modified product formed by a method of imparting elasticity to the resin component.
[0034]
For example, in the present invention, a urethane resin is described as an example of the resin for forming the solder resist coating solution. In the present invention, as the urethane resin forming the solder resist, (a) the number average molecular weight is 1000 to 8000. A polybutadiene polyol having a molecular weight of 2 to 10 hydroxyl groups per molecule, (b) a polyester polyol having a number average molecular weight of 13,000 to 30000 and having 2 to 10 hydroxyl groups per molecule; c) A polybutadiene polyblocked isocyanate having a number average molecular weight of 1000 to 8000 and having 2 to 10 hydroxyl groups per molecule is an essential component, and the weight ratio of polyol is (a) :( b) = 40:60 to 90:10, and the amount of polyblock isocyanate (c) is equivalent to the total hydroxyl groups of the polyol. A urethane resin contained in an amount of 0.8 to 3.5 equivalents relative to the amount is preferably used.
[0035]
With the component (a), it is possible to impart to the resin both the properties found in a rigid resin such as heat resistance and chemical resistance, and the properties found in a soft resin such as flexibility and low shrinkage. .
[0036]
When the molecular weight is smaller than the above specified range, or when the number of hydroxyl groups per molecule is larger than the above range, the crosslink density at the time of curing becomes high, so that the hardened product is obtained and the solder resist is flexible. And properties such as low shrinkage after curing may not be sufficiently imparted. Further, when the molecular weight is larger than the range specified above, when the number of hydroxyl groups per molecule is smaller than the above range, the crosslinking density at the time of curing becomes low, and the cured product has flexibility, but the cured product Heat resistance and chemical resistance are likely to decrease.
[0037]
The above component (b) gives the properties found in flexible cured products such as improved flexibility and low shrinkage after curing, and also improves adhesion to the substrate by a highly polar ester bond contained in the resin skeleton. It is something to be made.
[0038]
The component (c) imparts to the resin both the characteristics found in rigid resins such as heat resistance and chemical resistance, and the characteristics found in flexible resins such as flexibility and low shrinkage. When the molecular weight is smaller than the range specified above, when the number of hydroxyl groups per molecule is larger than the range specified above, the crosslink density after curing is increased, resulting in a harder cured product, Low shrinkage during curing may not be ensured sufficiently. On the other hand, when the molecular weight is smaller than this range, the crosslinking density at the time of curing is lowered, so that a more flexible cured product is obtained, but the heat resistance and chemical properties of the cured coating film may be lowered. Further, since the component (a) is a polybutadiene skeleton, the flexibility of the solder resist and the low shrinkage at the time of curing can be further improved.
[0039]
When polybutadiene polyol (a) is used alone and cured with polybutadiene polyisocyanate (b), properties such as heat resistance, chemical resistance, flexibility, and low shrinkage during curing are relatively balanced. Although easy, among these properties, there is room for further improvement in terms of flexibility, low shrinkage during curing, and adhesion to the substrate. In order to improve these properties, it is necessary to use a combination of polyester polyols. That is, (a) :( b) = 40: 60 to 90:10 are preferably mixed and used. If the polyol (a) is less than this range, the crosslinking density is too low. Characteristics such as heat resistance and chemical resistance are likely to deteriorate. The amount of the polybutadiene polyblock isocyanate (c) is preferably 0.8 to 3.5 equivalents relative to the total hydroxyl equivalent of the polyol, and the crosslink density is low in both cases where the amount is higher or lower. Therefore, the heat resistance and chemical resistance of the coating film may not be sufficiently improved.
[0041]
In the present invention, in addition to the resin components as described above, the solder resist coating solution contains a curing accelerator, a filler, an additive, a thixotropic agent, a solvent, etc., which are usually added to the solder resist coating solution. Can be added. Furthermore, in order to improve the characteristics such as flexibility of the solder resist layer, it is possible to blend fine particles having elasticity such as rubber fine particles.
[0042]
When stirring with a normal stirring device so that such a solder resist coating solution can be applied, fine bubbles are mixed in the coating solution, and the fine bubbles once mixed are removed by a normal method. It is very difficult to do. Therefore, conventionally, about 1 to 3% by weight of a silicone-based antifoaming agent is blended with respect to the resin component to prevent generation of fine bubbles and to prevent generation of voids or pinholes. However, even when the silicone-based antifoaming agent is used as described above, for example, when a propeller type stirring device, which is a general stirring device, is used, mixing of fine bubbles cannot be completely prevented.
[0043]
In the present invention, when mixing the solder resist coating liquid, it is preferable to use a stirring device as shown in FIG. 3 in which the container 61 rotates and the container 61 revolves. By using such a stirrer, the solder resist coating solution can be mixed well and fine bubbles mixed in the solder resist coating solution can be removed. The revolution speed at this time is preferably in the range of 1000 to 4000 rpm, and the rotation speed is in the range of 300 to 1200 rpm. The time required for the defoaming treatment using such an apparatus is usually 5 seconds to 15 minutes, preferably 1 to 10 minutes. By processing under such conditions, a large centrifugal force is continuously applied to the solder resist coating solution, and most of the fine bubbles contained in the solder resist coating solution are removed.
[0044]
Furthermore, in the present invention, the coating liquid that has been subjected to the defoaming treatment as described above is applied using a screen printing technique. Conventionally, a screen mask having a relatively small mesh size of about 180 mesh has been used for application of the solder resist coating liquid using this screen printing technique. In the present invention, such a conventionally used screen is generally used. Use a screen mask with a larger opening than the mask.
[0045]
  Especially in the present invention, Use a screen mask in the range of 120-165 mesh.By using such a screen mask, the solder resist coating thickness25-40 μmThe thickness of the solder resist can be increased as described above, so that pinholes can be prevented from being formed. In particular, in the TAB tape of the present invention in which the solder resist is thus thickened, it is preferable that the solder resist has elasticity. In the present invention, if an elastomer-modified product is used as the resin component of the solder resist, cracks and the like can be effectively prevented from being generated in the solder resist even when the solder resist is applied thickly.
[0046]
Such a solder resist coating solution is applied using a squeegee edge. Usually, as this squeegee edge, a plate-like squeegee edge having a flat bottom is used. Accordingly, the squeegee edge applies the solder resist while being in contact with the screen mask at a substantially right angle. However, such a plate-like squeegee edge with a flat bottom tends to reduce the amount of solder resist on the screen mask, making it difficult to ensure a sufficient coating thickness of the solder resist.
[0047]
In the present invention, as shown in FIG. 4, the squeegee edge 70 is at least 1/10, preferably 1/9 to 1/2 of the squeegee edge thickness, usually 45 degrees or less with respect to the screen mask 72. The cutout 71 is formed in the width direction so as to contact at an angle of, preferably 30 to 45 degrees. By forming the notch 71 in this way, more solder resist coating solution is retained in the notch 71 portion, and thick coating of the solder resist becomes possible.
[0048]
Further, in the present invention, when the solder resist coating liquid is applied using the squeegee edge 70 having such a notch 71, the speed on the screen mask 72 is usually within a range of 50 to 200 mm / second, preferably 80. The solder resist coating solution is applied by moving at a speed in the range of ˜150 mm / sec. In this way, by moving the squeegee edge 70 more slowly than before and applying the solder resist coating liquid, it becomes difficult for bubbles to be caught, and by forming the notch 71 in the squeegee edge 70, the bubble content is low. Since a large amount of solder resist coating solution can be supplied to the solder resist coating part of the screen mask, the content of bubbles is low so as to cover the wiring pattern formed on the insulating film without using a silicone-based antifoaming agent. The solder resist layer can be formed with a predetermined thickness. The solder resist layer thus formed does not substantially contain bubbles, so that no pinholes or voids are formed.
[0049]
  Furthermore, in this invention, after apply | coating a soldering resist coating liquid as mentioned above, by hardening | curing resin contained in this soldering resist layer on milder conditions, when a small amount of bubbles are contained temporarily However, after these bubbles disappear, the resin flows into the defoamed portion due to the self-leveling property of the solder resist, and generation of voids or pinholes can be prevented. That is, in the present invention, after applying the solder resist coating solution,40 ° C-170 ° CIn this range, the temperature is raised stepwise to remove the solvent contained in the solder resist layer and to cure the resin. As an example of the stepwise temperature increase at this time, the curing temperature in the first curing stage is set to 90 ° C. or lower, and the curing object is held in the first curing stage for 5 to 120 minutes, and then the temperature is gradually raised. To a second curing stage higher than 90 ° C. In this second curing stage, the object to be cured is held for 10 to 300 minutes at a temperature higher than 90 ° C., preferably about 95 to 180 ° C. The above example is an example of curing in two stages, but it may be a multistage of three or more stages in the same manner. When curing by setting the temperature in multiple stages as described above, it is preferable to raise the temperature under a mild condition as much as possible when heating from one curing stage to the next curing stage. For example, in the above example, As shown, the rate of temperature increase from the first curing stage to the second curing stage is usually 0.01 ° C./1 minute to 10 ° C./1 minute, preferably 0.1 ° C./1 minute to 5 ° C. / Must be within 1 minute.
[0050]
  For this heating, a normal air heater, hot air, a (far) infrared heater or the like can be used..
[0051]
    After forming the solder resist layer in this way, the wiring pattern and the insulating film on which the solder resist layer is formed are moved to a plating tank to form a tin plating layer on the surface of the wiring pattern..The tin plating layer is formed by a method such as electroless tin plating or electric tin plating. The initial tin-plated layer thus formed is usually substantially made of tin, but other metals may be contained within a range that does not impair the properties of the tin-plated layer.
[0052]
The thickness of the tin plating layer is preferably in the range of 0.1 to 0.6 μm. By forming the tin plating layer with such a thickness, when bonding the inner lead and the bump of the device, a metal such as gold forming the bump and tin form an appropriate amount of eutectic, so the inner lead and Bumps can be satisfactorily bonded, excessive eutectic is not formed, and even a fine pitch TAB tape is less likely to cause a short circuit at the inner lead portion during bonding. This tin plating layer is formed on the entire surface of the wiring pattern exposed from the portion where the solder resist layer is formed. By forming the tin plating layer in this way and heating, a part of the copper forming the lead diffuses into the tin plating layer, and the generation of whiskers from the lead portion can be suppressed. Further, after the tin plating layer is formed as described above, the formation of whiskers can also be controlled by performing tin plating (flash plating) so that a thin tin plating layer is formed on the surface of the formed tin plating layer. .
[0053]
In the above method, the plating layer is formed after the solder resist layer is formed, but the plating layer may be formed after the plating layer is formed and before the solder resist is applied. That is, after forming a wiring pattern by etching, the insulating film on which the wiring pattern is formed is transferred to a plating tank to form, for example, a tin plating layer, and then a solder resist is applied on the plating layer thus formed. Can do.
[0054]
A device can be bonded to the TAB tape thus formed according to a normal method.
[0055]
After the device is bonded in this way, resin is applied and the device is sealed according to a normal method. In the present invention, since no silicone-based antifoaming agent is used, such a sealing resin does not cause a sealing failure (adhesion failure) on the base film or the like.
[0056]
【The invention's effect】
The solder resist coating solution used in the present invention contains no silicone antifoaming agent. Thus, although the solder resist coating liquid of the present invention does not contain a silicone-based antifoaming agent, the coating thickness of the solder resist coating liquid, the improvement of the solder resist stirring method, the improvement of the coating apparatus, the printing method It is possible to prevent voids or pinholes from being generated in the solder resist layer by improvement or improvement of the drying method.
[0057]
Since the solder resist used in the present invention does not contain a silicone-based antifoaming agent, it is possible to bond the device to the inner lead satisfactorily, and after bonding the device, the portion including this device is made of resin. The silicone-based antifoaming agent that oozes out when sealed with does not deteriorate the sealing performance with the resin. Moreover, since the solder resist used in the present invention does not use a silicone-based antifoaming agent, there is an advantage that the entire factory is not contaminated with silicone.
[0058]
【Example】
EXAMPLES Next, the present invention will be described in more detail with reference to examples of the present invention, but the present invention is not limited thereto.
[0059]
[Example 1]
Device holes and sprocket holes were formed in a 75 μm thick polyimide film by punching. Next, an epoxy adhesive was applied to the polyimide film surface, and a copper foil having a thickness of 18 μm was adhered.
[0060]
Further, a photoresist was applied on the copper foil, the photoresist was exposed, and further etched to form a wiring pattern on the copper foil.
[0061]
Separately, a urethane-based solder resist coating solution that does not contain a silicone-based antifoaming agent is placed in a rotation / revolution stirrer (conditioning mixer MX-201, manufactured by Sinky Corporation), and a rotation speed of 600 rpm and a rotation speed of 2000 rpm. The defoamed urethane-based solder resist coating solution from which most of the contained fine bubbles were removed was obtained by stirring at a speed of 2 minutes.
[0062]
Next, a cut-out squeegee edge is arranged on the silk screen (mesh 150 mesh) with the tips of the inner leads and outer leads masked as shown in FIG. The defoamed urethane solder resist coating solution prepared as described above was supplied. Using the solder resist coating apparatus arranged as described above, the movement speed of the squeegee edge; 80 mm / sec so that the dry thickness of the urethane-based defoamed solder resist is 40 μm from above the formed wiring pattern; Coating was performed at a coating speed.
[0063]
After the solder resist was applied in this way, the temperature was raised stepwise to a temperature of 80 to 140 ° C. over 2.5 hours and heated to cure the solder resist. This heating was performed at normal pressure.
[0064]
After forming the solder resist layer in this way, this film was transferred to the electroless tin plating layer, and a tin plating layer was formed with a thickness of 0.2 μm on the surface of the wiring pattern on which the solder resist was not applied.
[0065]
After forming the tin plating layer, the TAB tape was held at a temperature of 120 ° C. for 1 hour.
[0066]
When the number of pinholes and voids in the solder resist layer was measured for 100 TAB tapes thus obtained, the average number of pinholes or voids generated per TAB tape was 0.01, which was substantially There were no voids or pinholes.
[0067]
As a result of measuring bonding failure with respect to 100 TAB tapes as described above, bonding failure was not substantially observed.
[0068]
The device was bonded to the TAB tape thus obtained, and the epoxy resin was applied to the portion including the device to seal the device. However, the sealing resin adhered well to the device and the TAB tape, and the sealing failure was I couldn't see it.
[0069]
In the present invention, the average number of pinholes or voids and bonding failure are average values measured with 100 TAB tapes as one unit.
[0070]
[Comparative Example 1]
Device holes and sprocket holes were formed in a 75 μm thick polyimide film by punching. Next, an epoxy adhesive was applied to the polyimide film surface, and a copper foil having a thickness of 18 μm was adhered.
[0071]
Further, a photoresist was applied on the copper foil, the photoresist was exposed, and further etched to form a wiring pattern on the copper foil.
[0072]
Separately from this, a urethane solder resist coating solution containing no silicone antifoaming agent was treated in the same manner as in Example 1 to obtain a defoamed urethane solder resist coating solution.
[0073]
Next, a squeegee edge with no notches formed on the edge is placed on a silk screen (mesh 180 mesh) with the inner lead and outer lead tips masked, and defoamed urethane prepared as described above. A solder resist coating solution was supplied, and in the same manner as in Example 1, a urethane-based defoaming solder resist was applied at a squeegee edge moving speed of 120 mm / sec so that the dry thickness was 20 μm. .
[0074]
The solder resist thus applied was cured in the same manner as in Example 1.
[0075]
After forming the solder resist layer in this way, this film was transferred to the electroless tin plating layer, and a tin plating layer was formed with a thickness of 0.2 μm on the surface of the wiring pattern on which the solder resist was not applied.
[0076]
After forming the tin plating layer, the TAB tape was held at a temperature of 120 ° C. for 1 hour.
[0077]
With respect to 100 TAB tapes thus obtained, the number of pinholes and voids in the solder resist layer was measured. The average number of pinholes or voids generated per TAB tape was 0.1. Became the main factor in the decline in yield.
[0078]
As a result of measuring bonding failure with respect to 100 TAB tapes as described above, bonding failure was not substantially observed.
[0079]
The device was bonded to the TAB tape thus obtained, and the epoxy resin was applied to the portion including the device to seal the device. However, the sealing resin adhered well to the device and the TAB tape, and the sealing failure was I couldn't see it.
[0080]
[Comparative Example 2]
Etching was performed in the same manner as in Example 1 to form a wiring pattern.
[0081]
Separately, a urethane solder resist containing 1% by weight of a silicone antifoaming agent was placed in a propeller type stirrer and stirred at 100 rpm for 15 minutes to obtain a urethane solder resist coating solution.
[0082]
Next, a squeegee edge with no notches formed on the edge is placed on a silk screen (mesh 180 mesh) with the inner lead and outer lead tips masked, and defoamed urethane prepared as described above. A solder resist coating solution was supplied, and in the same manner as in Example 1, a urethane-based defoaming solder resist was applied at a squeegee edge moving speed of 120 mm / sec so that the dry thickness was 25 μm. .
[0083]
The solder resist thus applied was cured in the same manner as in Example 1.
[0084]
After forming the solder resist layer in this way, this film was transferred to the electroless tin plating layer, and a tin plating layer was formed with a thickness of 0.2 μm on the surface of the wiring pattern on which the solder resist was not applied.
[0085]
After forming the tin plating layer, the TAB tape was held at a temperature of 120 ° C. for 1 hour.
[0086]
When the number of pinholes and voids in the solder resist layer was measured for 100 TAB tapes thus obtained, the average number of pinholes or voids generated per TAB tape was 0.01, which was substantially There were no voids or pinholes.
[0087]
As a result of measuring bonding failure with respect to 100 TAB tapes as described above, bonding failure was not substantially observed.
[0088]
The device was bonded to the TAB tape thus obtained, and an epoxy resin was applied to the portion including the device to seal the device. The sealing resin was repelled by 80 pieces on the base film near the device hole. There was a sealing failure.
[Brief description of the drawings]
FIG. 1 is a plan view schematically showing an example of a film carrier tape for mounting electronic components.
FIG. 2 is a cross-sectional view schematically showing an example of a film carrier tape for mounting electronic components.
FIG. 3 is a diagram schematically showing a rotation and revolution type stirring device.
FIG. 4 is a diagram schematically showing a squeegee edge used in the present invention.
[Explanation of symbols]
1 ... TAB tape
10 ... Insulating film
12 ... Adhesive layer
20 ... Solder resist
30 ... Copper foil (wiring pattern)
41 ... Device Hall
42 ... Sprocket hole
51 ... Inner lead
52 ... Outer lead
61 ... Container
70 ... Squeegee edge
71 ... Notch
72 ... Screen mask

Claims (2)

A screen mask in the range of 120 to 165 mesh of a defoaming solder resist coating solution containing a desired wiring pattern on the surface of the insulating film and containing urethane resin or a modified elastomer of urethane resin in a portion excluding the lead portion of the wiring pattern A solder resist layer having a thickness of 25 to 40 μm is formed of a cured product formed by heating the solder resist coating layer formed by coating using a coating stepwise within a range of 40 to 170 ° C. at normal pressure. The solder resist layer does not have pinholes or voids, and the film carrier tape has an inner lead to which no silicone antifoaming agent is attached , and the silicone antifoaming agent. the inner lead but unattached, tin plating thickness of 0.1~0.6μm which copper is diffused into a portion Film carrier tape for mounting electronic components, characterized in that There are formed.   The film carrier tape for mounting electronic parts according to claim 1, wherein the insulating film is a polyimide film.

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